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Name

sqitch-authentication - Guide to using database authentication credentials with Sqitch

Description

For database engines that require authentication, Sqitch supports a number of credential-specification options, and searches for them in a specific sequence. These searches are performed in two parts: a search for a username and a search for a password.

Usernames

Sqitch searches for usernames sequentially, using the first value it finds. Any of these approaches may be used to specify a username, in this order:

1. In the $SQITCH_USERNAME environment variable
2. Via the --db-username option
3. In the deploy target URI; this is the preferred option
4. In an engine-specific environment variable or configuration

Naturally, this last option varies by database engine. The details are as follows:

PostgreSQL

The Postgres engine uses the PGUSER environment variable, if set. Otherwise, it uses the system username.

MySQL

For MySQL, if the MySQL::Config module is installed, usernames and passwords can be specified in the /etc/my.cnf and ~/.my.cnf files. These files must limit access only to the current user (0600). Sqitch will look for a username and password under the [client] and [mysql] sections, in that order.

Oracle

Oracle provides no default to search for a username.

Vertica

The Vertica engine uses the VSQL_USER environment variable, if set. Otherwise, it uses the system username.

Firebird

The Firebird engine uses the ISC_USER environment variable, if set.

Exasol

Exasol provides no default to search for a username.

Snowflake

The Snowflake engine uses the SNOWSQL_USER environment variable, if set. Next, it looks in the ~/.snowsql/config file and use the default connections.username value. Otherwise, it uses the system username.

Passwords

You may have noticed that Sqitch has no --password option. This is intentional. It's generally not a great idea to specify a password on the command-line: from there, it gets logged to your command history and is easy to extract by anyone with access to your system. So you might wonder how to specify passwords so that Sqitch an successfully deploy to databases that require passwords. There are four approaches, in order from most- to least-recommended:

1. Avoid using a password at all
2. Use a database engine-specific password file
3. Use the $SQITCH_PASSWORD environment variable
4. Include the password in the deploy target URI

Each is covered in detail in the sections below.

Don't use Passwords

Of course, the best way to protect your passwords is not to use them at all. If your database engine is able to do passwordless authentication, it's worth taking the time to make it work, especially on your production database systems. Some examples:

PostgreSQL

PostgreSQL supports a number of authentication methods, including the passwordless SSL certificate, GSSAPI, and, for local connections, peer authentication.

MySQL

MySQL supports a number of authentication methods, plus SSL authentication.

Oracle

Oracle supports a number of authentication methods, including SSL authentication, third-party authentication, and, for local connections, OS authentication.

Vertica

Vertica supports a number of authentication methods including the passwordless TLS authentication, GSS authentication, and, for local connections, ident authentication.

Firebird

Firebird supports passwordless authentication only via trusted authentication for local connections.

Exasol

Exasol doesn't seem to support password-less authentication at this time; for other options, see the documentation.

Snowflake

Snowflake does not support password-less authentication.

Use a Password File

If you must use password authentication with your database server, you may be able to use a protected password file. This is file with access limited only to the current user that the server client library can read in. As such, the format is specified by the database vendor, and not all database servers offer the feature. Here's how the database engines supported by Sqitch shake out:

PostgreSQL

PostgreSQL will use a .pgpass file in the user's home directory to or referenced by the $PGPASSFILE environment variable. This file must limit access only to the current user (0600) and contains lines specify authentication rules as follows:

hostname:port:database:username:password
MySQL

For MySQL, if the MySQL::Config module is installed, usernames and passwords can be specified in the /etc/my.cnf and ~/.my.cnf files. These files must limit access only to the current user (0600). Sqitch will look for a username and password under the [client] and [mysql] sections, in that order.

Oracle

Oracle supports password file created with the ORAPWD utility to authenticate SYSDBA and SYSOPER users, but Sqitch is unable to take advantage of this functionality. Neither can one embed a username and password into a tnsnames.ora file.

Vertica

Vertica does not currently support a password file.

Firebird

Firebird does not currently support a password file.

Exasol

Exasol allows configuring connection profiles for the 'exaplus' client:

> exaplus -u sys -p exasol -c localhost:8563 -wp flipr_test
EXAplus 6.0.4 (c) EXASOL AG

Profile flipr_test is saved.
> exaplus -profile flipr_test -q -sql "select current_timestamp;"

CURRENT_TIMESTAMP
--------------------------
2017-11-02 13:35:48.360000

These profiles are stored in ~/.exasol/profiles.xml, readable only to the user by default. See the documentation for more information on connection profiles, specifically the EXAplus section in the chapter on "Clients and interfaces".

For ODBC connections from Sqitch, we can use connection settings in ~/.odbc.ini:

[flipr_test]
DRIVER = Exasol
EXAHOST = localhost:8563
EXAUID = sys
EXAPWD = exasol

When combining the above, Sqitch doesn't need to know any credentials; they are stored somewhat safely in ~/.exasol/profiles.xml and ~/.odbc.ini:

> sqitch status db:exasol:flipr_test
# On database db:exasol:flipr_test
# Project:  flipr
# ...
#
Nothing to deploy (up-to-date)
> sqitch rebase --onto '@HEAD^' -y db:exasol:flipr_test
Reverting changes to hashtags @v1.0.0-dev2 from db:exasol:flipr_test
  - userflips .. ok
Deploying changes to db:exasol:flipr_test
  + userflips .. ok
Snowflake

For Snowflake, Sqitch will read the ~/.snowsql/config file and use the default connections settings; named connections are not supported. An example:

[connections]
accountname = myaccount
region = us-east-1
username = frank
password = fistula postmark bag

The four variables that Sqitch currently reads are:

connections.accountname
connections.username
connections.password
connections.region

Use $SQITCH_PASSWORD

The $SQITCH_PASSWORD environment variable can be used to specify the password for any supported database engine. However use of this environment variable is not recommended for security reasons, as some operating systems allow non-root users to see process environment variables via ps.

The behavior of $SQITCH_PASSWORD is consistent across all supported engines, as is the complementary $SQITCH_USERNAME environment variable. Some database engines support their own password environment variables, which you may wish to use instead. However, their behaviors may not be consistent:

PostgreSQL

$PGPASSWORD

MySQL

$MYSQL_PWD

Vertica

$VSQL_PASSWORD

Firebird

$ISC_PASSWORD

Snowflake

$SNOWSQL_PWD

Use Target URIs

Passwords may also be specified in target URIs. This is not generally recommended, since such URIs are either specified via the command-line (and therefore visible in ps and your shell history) or stored in the configuration, the project instance of which is generally pushed to your source code repository. But it's provided here as an absolute last resort (and because web URLs support it, though it's heavily frowned upon there, too).

Such URIs can either be specified on the command-line:

sqitch deploy db:pg://fred:s3cr3t@db.example.com/widgets

Or stored as named targets in the project configuration file:

sqitch target add wigets db:pg://fred:s3cr3t@db.example.com/widgets

After which the target is available by its name:

sqitch deploy widgets

See sqitch-targets and sqitch-configuration for details on target configuration.

See Also

Sqitch

Part of the sqitch suite.